Protecting The Resistor Cable Against Short-Circuits; Mechanical Installation Of External Brake Resistors; Electrical Installation; Checking The Insulation Of The Assembly - ABB ACS880-04 Hardware Manual

236 Resistor braking
A thermal switch (standard in ABB resistors) is required for safety reasons. The thermal
switch cable must be shielded and may not be longer than the resistor cable. Wire the
switch to a digital input on the drive control unit as shown in the figure below.
+24VD
Θ
DIx

Protecting the resistor cable against short-circuits


The input fuses will also protect the resistor cable when it is identical with the input cable.

Mechanical installation of external brake resistors

All brake resistors must be installed outside the drive. Obey the resistor manufacturer's
instructions.

Electrical installation

Checking the insulation of the assembly


Obey the instructions given in section

Connection diagram


See section Power cable connection diagram example (6-pulse)

Connection procedure


•
Connect the resistor cables to the R+ and R- terminals in the same way as the other
power cables. If a shielded three-conductor cable is used, cut the third conductor and
ground the twisted shield of the cable (protective earth conductor of the resistor
assembly) at both ends
•
Connect the thermal switch of the brake resistor as described in section
system against thermal overload

Start-up

Set the following parameters (ACS880 primary control program):
•
Disable the overvoltage control of the drive by parameter 30.30 Overvoltage control.
•
Set parameter 31.01 External event 1 source to point to the digital input where the
thermal switch of the brake resistor is wired.
•
Set parameter 31.02 External event 1 type to Fault.
•
Enable the brake chopper by parameter 43.06 Brake chopper enable. If Enabled
with thermal model is selected, set also the brake resistor overload protection
parameters 43.08 and 43.09 according to the application.
•
Check the resistance value of parameter 43.10 Brake resistance.
With these parameter settings, the drive stops by coasting at brake resistor
overtemperature. For settings of other control programs, see the appropriate firmware
manual.
x
x
Brake resistor and resistor cable
on page 235.
on page 99.
on page 105.
Protecting the